1. Field of the Invention
The present general inventive concept relates to a unit including a built-in central processing unit (CPU) and an image forming apparatus using the same. More particularly, the present general inventive concept relates to a unit which becomes more secure by having a CPU with an operating system (OS), and an image forming apparatus using the same.
2. Description of the Related Art
As computers have become widely used, peripherals have also become widespread. Examples of peripherals are image forming apparatuses such as printers, scanners, copiers, and multifunction devices.
Image forming apparatuses use ink or toner to print images onto paper. Ink and toner are used whenever image forming operations are performed, until the ink or toner is finally exhausted. If ink or toner is empty, a user must replace a unit for storing the ink or toner. Such components which are replaceable while using the image forming apparatuses are referred to as consumables or replaceable units.
Among replaceable units, some units other than units which have to be replaced when the ink or toner is exhausted must be replaced after being used for a predetermined period of time. This is so even if ink or toner are not exhausted since properties of the units change after the predetermined period of time and the printing quality is thus reduced.
For example, a laser image forming apparatus includes a charge unit, a transfer unit, a fusing unit, and so on, and diverse kinds of rollers and belts used in each unit may be worn out or damaged due to use over a limited life span. As a result, the printing quality may be remarkably deteriorated. Therefore, the user has to replace such replaceable units at appropriate times.
The time to replace replaceable units can be determined using a use state index. The use state index represents an index to indicate the degrees of use of the image forming apparatus, for example, the number of pieces of paper printed by the image forming apparatus and the number of dots forming an image. The image forming apparatus can determine the time to replace replaceable units by measuring the number of pieces of paper printed by the image forming apparatus or the number of dots.
Recently, in order for the user to precisely determine the time to replace each replaceable unit, each replaceable unit has included a built-in customer replaceable unit monitoring memory (CRUM memory). The use state index of each replaceable unit is stored in the CRUM memory. Accordingly, even if each replaceable unit is separated and used in different image forming apparatuses, the use state of each replaceable unit can be determined precisely.
However, a conventional replaceable unit having a CRUM memory has a problem that users can easily access the CRUM memory. Information stored in the CRUM memory is very diverse, spanning from basic information regarding the manufacturer to information regarding the recent use state. If the information is modified, it is difficult to receive after-sale service and calculate the adequate time to replace the replaceable unit, resulting in degradation of image forming operations. In particular, if information regarding the manufacturer is modified, it is impossible to determine whether it is authentic and thus is difficult to manage the replaceable unit.